1. Technical Field
The present invention relates to a rechargeable battery and, more particularly, to a rechargeable battery which can improve productivity by improving an assembly structure of the battery.
2. Related Art
Generally, a rechargeable battery is a battery which is rechargeable and is different from a disposable battery which is not rechargeable. The rechargeable battery has been widely used in the fields of electronic devices, such as cellular phones, notebook computers and camcorders. Particularly, a lithium rechargeable battery has an operational voltage of 3.6 V which is three times higher than that of an Ni—Cd battery or an Ni—H battery, which are frequently used as power sources of electronic devices, and which have high energy density per unit weight. As a result, the lithium-ion battery has developed rapidly in recent years.
The lithium rechargeable battery includes a bare cell and a protection circuit module (PCM) for electrically protecting the operation of the bare cell. The bare cell comprises an electrode assembly including a cathode plate, an anode plate and a separator interposed between them, a can receiving the electrode assembly and an electrolytic solution, and a cap assembly sealing an opening part of the can.
Methods of fixing the protection circuit module to the bare cell include a molding method using injected melted resin and an assembling method using an injection molded case.
The method of fixing the protection circuit module to the bare cell by molding melted resin has a problem in that the high temperature of the melted resin causes undesirable effects on various elements included in the protection circuit module. Furthermore, it is difficult to form a molding resin at an exact position on one surface of the bare cell, thereby increasing defects.
Conversely, the method of fixing the protection circuit module to the bare cell by the injection molded case does not affect the elements of the protection circuit module by hot temperature, and since it is an assembling method using a case, it is always possible to assemble at an exact position of the bare cell. In addition, the assembling process is simple.
However, in the fixing method using the case, the case is fixed to the bare cell by a label sheet surrounding an outer circumference surface of the bare cell. In this regard, the case is fixed to the bare cell by adhesive force of the label sheet, which is a thin film, and thus the binding force of the case attached to the bare cell is very weak. Accordingly, the case is easily twisted from an upper surface of the bare cell or, in an undesirable case, may be separated from the bare cell.
As described above, the conventional case is easily separated from the bare cell because the case is fixed to the bare cell only by the adhesive force of the label sheet. Thus, there is a problem that the reliability of products is prominently damaged.